diff --git a/ansible/inventory/group_vars/desktop.yml b/ansible/inventory/group_vars/desktop.yml
index d2a6413..69d2baf 100644
--- a/ansible/inventory/group_vars/desktop.yml
+++ b/ansible/inventory/group_vars/desktop.yml
@@ -137,3 +137,6 @@ desktop_flatpak_packages:
   - io.github.flattool.Warehouse
   - org.telegram.desktop
   - sh.loft.devpod
+
+desktop_flatpak_extensions:
+  - org.gtk.Gtk3theme.Yaru-Blue-dark
diff --git a/ansible/roles/profile_desktop_i3/tasks/main.yml b/ansible/roles/profile_desktop_i3/tasks/main.yml
index 91c321c..ac179f1 100644
--- a/ansible/roles/profile_desktop_i3/tasks/main.yml
+++ b/ansible/roles/profile_desktop_i3/tasks/main.yml
@@ -273,6 +273,42 @@
     method: system
   when: (desktop_flatpak_packages | default([])) | length > 0
 
+- name: Gather Flatpak runtime branches for extensions
+  ansible.builtin.shell: >-
+    flatpak list --runtime --columns=application,branch --system
+    | awk '$1 == "org.gnome.Platform" || $1 == "org.freedesktop.Platform" { print $2 }'
+    | sort -u
+  register: desktop_flatpak_runtime_branches
+  changed_when: false
+  when:
+    - (desktop_flatpak_packages | default([])) | length > 0
+    - (desktop_flatpak_extensions | default([])) | length > 0
+
+- name: Build Flatpak extension refs for active runtimes
+  ansible.builtin.set_fact:
+    desktop_flatpak_extension_refs: >-
+      {{
+        (desktop_flatpak_extensions | default([]))
+        | product(desktop_flatpak_runtime_branches.stdout_lines | default([]))
+        | map('join', '//')
+        | list
+      }}
+  when:
+    - (desktop_flatpak_packages | default([])) | length > 0
+    - (desktop_flatpak_extensions | default([])) | length > 0
+
+- name: Install Flatpak extensions for active runtimes
+  community.general.flatpak:
+    name: "{{ item }}"
+    state: present
+    remote: "{{ desktop_flatpak_remote_name | default('flathub') }}"
+    method: system
+  loop: "{{ desktop_flatpak_extension_refs | default([]) }}"
+  when:
+    - (desktop_flatpak_packages | default([])) | length > 0
+    - (desktop_flatpak_extensions | default([])) | length > 0
+    - item | length > 0
+
 - name: Set desktop external tool release metadata
   ansible.builtin.set_fact:
     desktop_tools_tmp_dir: /tmp/desktop-tools
diff --git a/dotfiles/desktop/.config/i3/scripts/setup-gtk-theme.sh b/dotfiles/desktop/.config/i3/scripts/setup-gtk-theme.sh
index 0d02825..995105e 100755
--- a/dotfiles/desktop/.config/i3/scripts/setup-gtk-theme.sh
+++ b/dotfiles/desktop/.config/i3/scripts/setup-gtk-theme.sh
@@ -35,3 +35,10 @@ EOF
 export GTK_THEME=$THEME
 export XCURSOR_THEME=$CURSOR
 export XCURSOR_SIZE=24
+
+if command -v gsettings >/dev/null 2>&1; then
+  gsettings set org.gnome.desktop.interface gtk-theme "$THEME" >/dev/null 2>&1 || true
+  gsettings set org.gnome.desktop.interface icon-theme "$ICONS" >/dev/null 2>&1 || true
+  gsettings set org.gnome.desktop.interface cursor-theme "$CURSOR" >/dev/null 2>&1 || true
+  gsettings set org.gnome.desktop.interface color-scheme prefer-dark >/dev/null 2>&1 || true
+fi